This invention relates generally to a piston ring compressor and more particularly to a piston ring compressor for compressing piston rings around grooves of a piston.
The introduction of a piston assembly into a cylinder bore of a combustion engine is a complex and awkward process. In order to accomplish this task, piston rings must be compressed around grooves of the piston while the entire piston assembly (including the connecting rod) is properly oriented and positioned with respect to the cylinder bore of the engine block. This process is further complicated by the fact that an operator or technician must apply a substantial amount of compression about the piston rings while at the same time installing the piston assembly into the cylinder bore of the engine block.
Many piston ring compressors are currently known and commercially used throughout the industry. One type of piston ring compressor includes a piston ring clamp having two ring halves connected together at one end by a hinge joint and at opposite ends by a screw device. The ring halves are pivoted into an open position and are positioned around the piston rings, and are then moved to a closed position for clamping and compressing the piston rings. The entire piston assembly is then pushed through the clamp into the cylinder of the engine block. An adjustable member such as, for example, a ratchet mechanism, is provided between the separable ends of the ring halves to adjust an inside diameter of the piston ring compressor. This prevents the ring halves from engaging the outer surface of the piston, thus ensuring that the piston assembly can be pushed out of the clamp and into the cylinder of the engine block. However, this piston ring compressor does not apply uniform compressive forces around the circumference of the piston rings, and cause a greater compressive force on portions of the piston ring than remaining portions of the piston ring. This non-uniform compressive force not only damages the piston rings but also hinders the ability of the piston assembly to slide through the clamp into the cylinder. A non-uniform compressive force may also require the operator or technician to apply a greater force during the insertion of the piston assembly into the cylinder. This, of course, adds to the awkward nature of inserting the piston assembly into the cylinder.
Another type of piston ring compressor uses overlapping bands to compress the piston rings about the piston. In these applications, two end sections of the band are attached via a lever. The lever is then actuated to compress the piston rings about the piston grooves. It is noted that in these piston ring compressors, an outer band of the piston ring compressor overlaps an inner band of the ring compressor. The overlapping bands provide an uneven compressive force about the piston rings and most notably an undue stress in the piston rings at the inner end of the inner band of the overlapping bands. It is further noted that the inner band tends to catch on the piston rings during the compression of the outer band, and in some instances prevents the piston assembly from being removed from the band and into the cylinder of the engine block.
In yet another type of piston ring compressor, a ring is provided which has a varying inner circumference. A lower portion of the ring has an inner circumference which is slightly smaller than the circumference of the piston rings, while an upper end of the ring has an inner circumference which is much smaller than the circumference of the piston rings (in an uncompressed state). In this type of piston ring compressor, the operator or technician places the larger diameter side of the piston ring compressor around the piston rings. As the piston assembly is slid through the piston ring compressor, the piston rings are compressed. In this system, the piston ring compressor tends to get caught on the piston rings during the initial mounting stage. This, in turn, damages the piston rings as well as uncouples the piston rings from the grooves of the piston.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a piston ring compressor is provided. The piston ring compressor has a wall forming a hollow shaped member which has a first end and a second end. An inner compression surface is formed about the hollow shaped member which has a diameter which gradually decreases from the second end to the first end.
In another aspect of the present invention, a piston ring is provided with a first and second wall having an inner compression surface. A hinge connects the first and second walls. When the first and second walls are moved to the closed position, the hollow shaped member is formed. The hollow shaped member has a diameter which gradually increases from a first end to a second end.